Northampton County authorities on Tuesday said a couple facing charges that they let their 6-year-old girl's teeth rot are being investigated in the deaths of three of their children going back to 2007, including two stillborns and a baby boy.

Authorities said that when Jessica Hoffman had a 34-week-old stillborn boy in December, she tested positive for methamphetamine use and that triggered the probe of her and the father, Kenneth Wanamaker Jr., leading to charges of dental neglect.

During a court hearing Tuesday, a caseworker revealed that Hoffman tested positive for meth when she went to the hospital and had the 34-week-old stillborn.

"The whole thing is under investigation now because we want to make sure all these children are safe and being properly cared for," District Attorney John Morganelli said Tuesday, referring to the Lehigh Township couple's other children.

Authorities said the couple have two children together, and Hoffman has a son from a previous relationship who sometimes lives with them.

"We are revisiting all the cases; we are revisiting all the deaths," Morganelli said, adding that the cases are all "under the same umbrella."

The couple brought the 7-month-old boy and the two stillborns to hospitals in Lehigh County, where Coroner Scott Grim investigated the deaths.

He said Tuesday that the 2013 stillborn death of 34-week-old Krystopher Cole Wanamaker that prompted the investigation of his parents was due to "maternal methamphetamine use."

The 7-month-old boy, Tyson Cole Wanamaker, died Nov. 14, 2011, due to complications of chronic pneumonia and his death was ruled natural, Grim said.

@gramobam Yes they should investigate now, but just because a person lives in a trailer where they run their business from is not a cause to investigate. Unless it is an illegal business. Neither is one living in a trailer with no water. When I bought my second house it had spring water. Well...

In Pennsylvania, the coroner's office is required to investigate any stillborn deaths beginning at 16 weeks' gestational age, authorities said.

In stillborn death investigations, only the cause and not the manner is listed on death certificates, Grim said.

While recognizing the constitutionally protected right to abortion, Pennsylvania law makes it a crime to kill an unborn child. But the statute doesn't apply to the pregnant mother, who is exempted from criminal liability altogether "in regard to crimes against her unborn child."

Morganelli said even a fetus death caused by the mother's drug use would likely not result in criminal charges. And a woman who threw herself down the stairs during her pregnancy could not be charged with her fetus' death. But if her husband threw her down the stairs, he could be charged.

On June 26, the day after the couple were charged in the dental neglect case, Morganelli said he assigned a detective to the case after a reporter with The Morning Call asked about the circumstances of the other deaths.

"Can you look into why these kids are all dying?" Morganelli said he wrote in an email to his detective.

At Tuesday's hearing on the alleged neglect of the girl's teeth, Assistant District Attorney Patricia Broscius amended the complaint against Wanamaker and Hoffman from a misdemeanor to a felony charge of endangering the welfare of a child.

Broscius said the couple ignored caseworkers' requests to get the girl dental surgery, which showed criminal behavior. District Judge Robert Hawke approved the amended complaint.

Hoffman, 31, remains free after posting $40,000 bail. She was also cited Tuesday with harassment after she allegedly shoved a Morning Call photographer outside Hawke's courtroom in Lehigh Township.

Although Wanamaker was also free under the same bail, Hawke forfeited his bail after Wanamaker allegedly failed to comply with bail conditions that included urine tests and check-ins with authorities. Wanamaker, 37, is in county prison under $75,000 bail.

After Tuesday's hearing, Hoffman's attorney, Michael P. Gough, said he expects her to regain "physical and legal custody" of her children.

During the nearly three-hour hearing, witnesses said the couple's 6-year-old daughter was supposed to have surgery in March for numerous rotted teeth, but Wanamaker and Hoffman failed to take her.

In court records, Dr. Eugene McGuire told authorities the decay is "the worst case of dental disease" he had ever seen and the infection could kill her.

McGuire testified Tuesday, calling the girl's dental decay "frightening." He said 16 of the girl's 20 teeth were either abscessed, needed to be pulled or had severe root and tooth decay.

He said the girl was examined Feb. 26 by his son, a dentist at the same practice. But McGuire said he reviewed his son's notes and approved of the recommended treatment — a surgery that would require the girl to undergo anesthesia.

McGuire testified that although his office attempted to schedule the surgery, his staff told him that Hoffman hung up on them during one phone call and said in another the girl would not undergo the surgery.

McGuire said he later assumed the girl had been treated by another dentist, but learned in mid-June that the parents still had not sought treatment for the girl. McGuire testified he told Wanamaker, "Please make sure this child gets treated."

Northampton County Children and Youth caseworker Jessica Yandle testified Tuesday that her office began investigating Wanamaker and Hoffman after the stillborn death in 2013 and said Hoffman tested positive for meth use.

Yandle said although Hoffman was asked by caseworkers to submit urine tests in December and January, she did not comply until April.

The caseworker said she spoke with Wanamaker and Hoffman's daughter at her school in May. Yandle said that during that school visit, she noted the girl's teeth were "in very poor condition" and called McGuire's office. McGuire's name was listed in caseworker records.

Yandle said McGuire's office told her the girl had been scheduled for surgery, but the procedure was never completed. Yandle testified she then told Wanamaker the girl needed an antibiotic immediately and asked why the surgery was not completed.

She testified the couple balked at the $5,000 price tag for the procedure, saying they could not afford it. Yandle said Wanamaker also told her McGuire had told him the surgery wasn't necessary because the girl's decaying teeth were baby teeth and would fall out eventually.

"The parents didn't feel like it was worth spending the money," Yandle testified.

She said that after the Feb. 26 visit with McGuire, Hoffman and Wanamaker changed dental insurance providers. She said the couple sought a second dental opinion and the girl later received care.